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mbolding / cinl

Civitan International Neuroimaging Laboratory
https://www.uab.edu/medicine/circ/neuroimaging
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possible abnormal shimming behavior during GRE fieldmap scans #188

Closed jtotenha closed 3 years ago

jtotenha commented 7 years ago

prescan adjusments seem to be taking longer than usual, displays frequency adjust - 3d shim - frequency adjust - 3d shim - frequency adjust

does this usually take so long and repeat the freq-shim-freq cycle so many times?

jtotenha commented 7 years ago

is this related to the shimming issues with the SVS and CSI?

is this something that will be checked during the PM visit?

mbolding commented 7 years ago

Dr. Bolding,

Thanks for looking into this for us. After chatting with David and Dr. Lahti yesterday, it seems that we often have trouble with the scans after running the MPFC Megapress sequence. I wanted to let you know in case there was any significance. And of course, we are more than happy to remove this sequence from the protocol if it is indeed causing a problem.

Thanks,

jtotenha commented 7 years ago

probably related to the "advanced shim" mode used in EPI scans,

this is found in the protocols under the system tab, adjustments, shim mode

see the following from UC Berkeley's MRI center: https://practicalfmri.blogspot.com/2013/03/quick-update-for-siemens-users.html